Spi 21-996-4 Test Indicator Ball Contact Point

Product Description

The SPI 21-996-4 is a ball-style contact point designed for use with dial test indicators in precision measurement applications. The contact tip is a 0.118-inch diameter stainless steel ball, and the overall contact point length is 0.64 inches. This replacement contact point threads into compatible test indicators and is used by machinists, tool-and-die makers, and calibration technicians who need accurate surface contact during indicator runout, alignment, or inspection work. The stainless steel construction resists wear and corrosion under typical shop conditions.

This contact point is suited for precision measurement environments including machine shops, toolrooms, and quality control inspection stations. It is used when checking bore runout, surface concentricity, or part alignment on milling machines, lathes, and surface plates. The ball tip geometry allows contact on curved or irregular surfaces where a flat or pointed tip would introduce cosine error or slip off the workpiece.

Key Features

• 0.118-inch (3.00 mm) stainless steel ball tip for contact on curved and flat surfaces
• Contact point length of 0.64 inches (16.30 mm) for standard indicator reach
• Stainless steel construction resists wear and corrosion in shop environments
• Replacement-ready design for field or bench swapping without special tools
• Sold individually — package quantity of 1

Compatibility

Designed for use with the SPI Integral Series test indicators.

Installation Notes

Contact points on dial test indicators are typically threaded and can be removed and reinstalled by hand or with a small wrench — avoid overtightening, which can damage the indicator spindle threads. Power-down or lock out any machine before mounting or repositioning an indicator and contact point assembly. Always verify indicator zeroing and contact point seating after a tip change before taking measurements.